Drive sprocket for a tracked vehicle

ABSTRACT

A drive sprocket for driving a track of a tracked vehicle is provided. The drive sprocket includes an interior ring, an exterior ring, and an intermediate ring situated between the interior ring and the exterior ring. The interior ring, exterior ring, and intermediate ring are oriented in a substantially spaced-apart manner, each of the rings have an outer peripheral surface. A plurality of rods is attached to the rings adjacent to the outer peripheral surface thereof. The interior, exterior, and intermediate rings have a substantially “U” or “J” shape.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/381,003 filed Dec. 15, 2016, which is a continuation of Ser. No.14/484,993 filed Sep. 12, 2014, which claims benefit of U.S. ProvisionalPatent Application Ser. No. 61/877,584, filed Sep. 13, 2013, andentitled “DRIVE SPROCKET FOR A TRACKED VEHICLE”, which are hereinincorporated by reference in their entireties.

FIELD OF THE INVENTION

The present invention is directed to a drive sprocket, and moreparticularly, a drive sprocket for a tracked vehicle having asuspension.

BACKGROUND OF THE INVENTION

Track drive machines typically include those with metal or compositecleats that are connected together to form continuous loops and thoseconstructed of reinforced polymer/rubber materials that are manufacturedin endless loops.

Tracked vehicles are typically designed so as to produce groundpressures lower than that of wheeled vehicles. Heavy machines aretypically below 15 lb/in², but lightweight machines are ranging as lowas 1 to 3 lb/in². The stiffness of the track is selected to minimizeflexing between the bogie wheels. The track is therefore keptsubstantially straight between the bogie wheels, idlers, and the drivesprocket to increase the efficiency associated with transference ofpower to the tracks and losses due to misalignment. Track tension,especially for non-metallic endless-loop configurations, must bemaintained within prescribed parameters in order to prevent buckling inslack sections.

Drive sprockets are sometimes positioned above the ground to reducecontamination, reduce complexity in the design while effectivelytransmitting power to the tracks. Positioning the drive sprockets aboveground also helps to prevent derailing of the track. Tracks aregenerally held in a constant state of tension on the drive sprocket andthe roller, and this also helps to prevent derailment.

These offerings have limitations in performance in regard to lateralderailment of tracks, drive lug skipping (ratcheting), and backlashimpacts from sprocket engagement to drive lug during traction directionload reversals.

A need therefore exists for a drive sprocket for a tracked vehicle inwhich the drive sprocket maintains closer engagement with guide lugs ontrack. A need also exists for a drive sprocket for a tracked vehiclethat reduces the wear and increases the longevity of the guide lugs andadjacent lugs on the track.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the invention, a drive sprocket for driving a track ofa tracked vehicle comprises: a pair of spaced-apart inner rings, whereinthe inner rings are oriented in a substantially spaced-apart manner,each of the inner rings having an outer peripheral edge; a plurality ofrods attached to the inner rings adjacent to the outer peripheral edgethereof; and a pair of guide rings fixedly attached to the rods, whereineach of the guide rings is attached adjacent to an opposing end of therods, the guide rings being oriented substantially parallel to eachother and the inner rings.

In another aspect of the drive sprocket, a spacer is positioned betweenthe inner rings, the spacer being fixedly attached to the inner rings.

In another aspect of the drive sprocket, an adapter is attached to anoutwardly-directed surface of one of the pair of inner rings.

In another aspect of the drive sprocket, a slide ring is attached to anoutwardly-directed surface of each of the guide rings.

In another aspect of the drive sprocket, an outwardly-directed surfaceof each of the guide rings is coated with a friction-reducing material.

In another aspect of the drive sprocket, each of the plurality of rodsis spaced-apart from adjacent rods.

In another aspect of the drive sprocket, the plurality of rods form aplurality of clusters, wherein each of the clusters is formed of a pairof the rods and each of the cluster is spaced-apart from adjacentclusters about the peripheral edge of the inner rings.

In another aspect of the drive sprocket, the rods are cylindricallyshaped having a circumferential surface.

In another aspect of the drive sprocket, a portion of thecircumferential surface of the rods extend radially outward away fromthe outer peripheral surface of the inner rings relative to a rotationalaxis of the drive sprocket.

In another aspect of the drive sprocket, a portion of thecircumferential surface of the rods extend radially outward away fromthe outer peripheral surface of the guide rings relative to a rotationalaxis of the drive sprocket.

In another aspect of the drive sprocket, a portion of thecircumferential surface of the rods extend radially outward away fromthe outer peripheral surface of the inner rings relative to a rotationalaxis of the drive sprocket, and a portion of the circumferential surfaceof the rods extend radially outward away from the outer peripheralsurface of the guide rings relative to a rotational axis of the drivesprocket.

In yet another aspect of the invention, a drive sprocket for driving atrack of a tracked vehicle comprises: an interior ring, an exteriorring, and an intermediate ring situated between the interior ring andthe exterior ring; the interior ring, the exterior ring, and theintermediate ring are oriented in a substantially spaced-apart mannerand are parallel with one another, each of the rings having an outerperipheral surface; and a plurality of rods attached to the ringsadjacent to the outer peripheral surface thereof.

In another aspect of the invention, the interior ring has asubstantially “U” or “J” shape.

In another aspect of the invention, the an inner guide ring, an outerguide ring, and a base ring of the interior ring form the substantially“U” or “J” shape of the interior ring. The base ring is located betweenthe inner guide ring and the outer guide ring.

In another aspect of the invention, the base ring, the inner guide ring,and a first portion of the outer guide ring of interior ring form thesubstantially “U” shape of the interior ring.

In another aspect of the invention, the exterior ring has asubstantially “U” or “J” shape.

In another aspect of the invention, an inner guide ring, an outer guidering, and a base ring of the exterior ring form the substantially “U” or“J” shape of the exterior ring. The base ring is located between theinner guide ring and the outer guide ring of the exterior ring.

In another aspect of the invention, the base ring, the outer guide ring,and a first portion of the inner guide ring of the exterior ring formthe substantially “U” shape of the exterior ring.

In another aspect of the invention, the intermediate ring has asubstantially “U” or “J” shape.

In another aspect of the invention, an inner guide ring, an outer guidering, and a base ring of the intermediate ring form the substantially“U” or “J” shape of the intermediate ring. The base ring is locatedbetween the inner guide ring and the outer guide ring of theintermediate ring.

In another aspect of the invention, the base ring, the inner guide ring,and a first portion of the outer guide ring of the intermediate ringform the substantially “U” shape of the intermediate ring.

In another aspect of the invention, the “U” or “J” shape of the interiorring is configured to substantially fill the space between an interiorguide lug and an interior drive lug arranged in an annular pattern on aninside surface of a track.

In another aspect of the invention, the “U” or “J” shape of theintermediate ring is configured to substantially fill the space betweenan exterior drive lug and an interior drive lug arranged in an annularpattern on an inside surface of a track.

In another aspect of the invention, the “U” or “J” shape of the exteriorring is configured to substantially fill the space between an exteriorguide lug and an exterior drive lug arranged in an annular pattern on aninside surface of a track.

In another aspect of the invention, the base ring of the interior ringis further comprised of a flat outer peripheral surface located betweenthe rods and the inner guide ring and the outer guide ring of theinterior ring.

In another aspect of the invention, the base ring of the exterior ringis further comprised of a flat outer peripheral surface located betweenthe rods and the inner guide ring and the outer guide ring of theexterior ring.

In another aspect of the invention, the base ring of the intermediatering is further comprised of a flat outer peripheral surface locatedbetween the rods and the inner guide ring and the outer guide ring ofthe intermediate ring.

In another aspect of the invention, each of the plurality of rods isspaced-apart from adjacent rods.

In another aspect of the invention, the plurality of rods form aplurality of clusters, wherein each of the clusters is formed of a pairof the rods and each of the clusters is spaced apart from adjacentclusters about the peripheral edge of the inner rings.

In another aspect of the invention, the rods are cylindrically shapedhaving a circumferential surface.

In another aspect of the invention, a portion of the circumferentialsurface of the rods extends radially outward away from the outerperipheral surface of the interior ring relative to a rotational axis ofthe drive sprocket.

In another aspect of the invention, a portion of the circumferentialsurface of the rods extends radially outward away from the outerperipheral surface of the exterior ring relative to a rotational axis ofthe drive sprocket.

In another aspect of the invention, a portion of the circumferentialsurface of the rods extends radially outward away from the outerperipheral surface of the intermediate ring relative to a rotationalaxis of the drive sprocket.

In another aspect of the invention, an adapter is fixed to an outerguide ring of the interior ring, wherein the adapter is configured to bedirected toward a tracked vehicle when the drive sprocket is mounted onthe tracked vehicle.

In another aspect of the invention, a spoke assembly is fixed to theouter guide ring of the interior ring; the spoke assembly is configuredto be directed away from the tracked vehicle when the drive sprocket ismounted on the tracked vehicle; the spoke assembly ring has a pluralityof spokes projecting toward the radial periphery of the drive sprocket;the spokes form an acute angle with respect to the outer guide ring.

In another aspect of the invention, each of the spokes has a ring end, adistal end, and an intermediate position located between the ring endand the distal end; the exterior ring is fixed to the distal end of thespokes and the intermediate ring is fixed to the spokes at theintermediate position.

Advantages of the present invention will become more apparent to thoseskilled in the art from the following description of the embodiments ofthe invention which have been shown and described by way ofillustration. As will be realized, the invention is capable of other anddifferent embodiments, and its details are capable of modification invarious respects.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

These and other features of the present invention, and their advantages,are illustrated specifically in embodiments of the invention now to bedescribed, by way of example, with reference to the accompanyingdiagrammatic drawings, in which:

FIG. 1A is an end view of a first exemplary embodiment of a drivesprocket;

FIG. 1B is a view of a first exemplary embodiment of a drive sprockettaken along line 1B of FIG. 1A;

FIG. 1C is a perspective view of a first exemplary embodiment of a drivesprocket;

FIG. 2A is an end view of a second exemplary embodiment of a drivesprocket;

FIG. 2B is a view a second exemplary embodiment of a drive sprockettaken along line 2B of FIG. 2A;

FIG. 2C is a perspective view of a second exemplary embodiment of adrive sprocket; and

FIGS. 3A-B are perspective views of an embodiment of a drive sprocket ona tracked vehicle.

FIG. 4 is a perspective view of the front of a third exemplaryembodiment of a drive sprocket.

FIG. 5 is a perspective view of the back of a third exemplary embodimentof a drive sprocket.

FIG. 6 is an end view of a third exemplary embodiment of a drivesprocket.

FIG. 7 is a close up front view of a third exemplary embodiment of adrive sprocket.

FIG. 8 is an isometric view of the front of a third exemplary embodimentof a drive sprocket on a tracked vehicle.

It should be noted that all the drawings are diagrammatic and not drawnto scale. Relative dimensions and proportions of parts of these figureshave been shown exaggerated or reduced in size for the sake of clarityand convenience in the drawings. The same reference numbers aregenerally used to refer to corresponding or similar features in thedifferent embodiments. Accordingly, the drawing(s) and description areto be regarded as illustrative in nature and not as restrictive.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Approximating language, as used herein throughout the specification andclaims, may be applied to modify any quantitative representation thatcould permissibly vary without resulting in a change in the basicfunction to which it is related. Accordingly, a value modified by a termor terms, such as “about”, is not limited to the precise valuespecified. In at least some instances, the approximating language maycorrespond to the precision of an instrument for measuring the value.Range limitations may be combined and/or interchanged, and such rangesare identified and include all the sub-ranges stated herein unlesscontext or language indicates otherwise. Other than in the operatingexamples or where otherwise indicated, all numbers or expressionsreferring to quantities of ingredients, reaction conditions and thelike, used in the specification and the claims, are to be understood asmodified in all instances by the term “about”.

“Optional” or “optionally” means that the subsequently described eventor circumstance may or may not occur, or that the subsequentlyidentified material may or may not be present, and that the descriptionincludes instances where the event or circumstance occurs or where thematerial is present, and instances where the event or circumstance doesnot occur or the material is not present.

As used herein, the terms “comprises”, “comprising”, “includes”,“including”, “has”, “having”, or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article or apparatus that comprises a list of elements is notnecessarily limited to only those elements, but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus.

The singular forms “a”, “an”, and “the” include plural referents unlessthe context clearly dictates otherwise.

The proposal provides for metallic or composite material sprocket with acentral hub with radial extensions (such as discs or spokes) to connectwith teeth equally spaced in an annual arrangement. The teeth are spacedto engage the track drive lugs near their tooth roots and to match thetrack pitch length in a neutral or a slightly under-pitch condition.

The drive sprocket is provided with rod-shaped teeth that engage thetraction drive lugs of the tracks close to the traction drive lug pitchline so as to reduce bending moments and stress on the drive lugs. Thesprocket teeth do not appreciably “scrub” the areas between the drivelugs during traction drive load force reversals such as during machineacceleration and deceleration and turning maneuvers. One embodimentshown includes two (or more) rods to further minimize the backlash. Thisreduction in backlash also reduces the propensity for track drive lugskipping. In other embodiments, only one rod is present at each driverod-tooth location.

The drive sprocket includes a pair of guide rings that attach to thedrive rod-teeth, and they laterally engage guide lugs during turningmaneuvers to prevent track derailment. These rings greatly strengthenthe drive rod-teeth and help to increase the contact areas of the teethwhile also reducing track deformation (flexing of the rods without thering supports allow a crowning effect of the tracks at the sprockets).In one embodiment, these rings are equipped with low friction materialsto reduce scrub friction with the guide lugs. In other embodiments, alow friction material is not present on the guide rings.

The following features are incorporated:

-   -   A sprocket incorporating a central drive hub, radial extensions        to connect with teeth, single rod-shaped teeth annularly spaced        at the pitch-length of the track, and rings attached to the        teeth    -   Same as above but with multiple rods at each tooth location    -   Same as above, but with low-friction materials coated onto or        attached to the rings    -   Same as above but with the teeth annularly spaced at less than        the pitch-length of the track, up to 1% under-pitch

In the embodiment illustrated in FIGS. 1A-C, the drive sprocket 10includes a pair of substantially circular inner rings 12. A spacer 14 ispositioned between the pair of inner rings 12 to allow the inner rings12 to be spaced apart. The thickness of the spacer 14 is between about0.10 inches and about 3.0 inches. The spaced-apart inner rings 12provide lateral stiffness to the drive sprocket 10, particularly withrespect to the lateral forces experienced during a turn of the vehicle.The spacer 14 is sandwiched between the inner rings 12. An adapter 16 ispositioned adjacent to the outwardmost inner ring 12 relative to thevehicle when the drive sprocket 10 is operatively connected to thevehicle. The adapter 16 is configured to engage a drive shaft or otherrotatable shaft that operatively transfers rotation from the engine tothe drive sprocket 10. When the drive sprocket 10 is installed onto thedrive shaft, the adapter 16 is directed away from the vehicle.

In an embodiment, the inner rings 12 and the spacer 14 can be formed asa single member having an equivalent thickness. The spacer 14 allows theinner rings 12 to provide the structural integrity to the rods 18 whilereducing the weight of the drive sprocket 10. In a similar manner, theadapter 16 can also be formed as having a diameter that is substantiallythe same as the inner rings 12. The spacer 14 and adapter 16 areattached to the inner rings 12 to allow the drive sprocket 10 to beattached to the drive shaft from an engine while transferring therotational force to the inner rings 12. In another embodiment, the innerrings 12, spacer 14, and adapter 16 all include a common aperture shapedto receive the drive shaft (not shown) that provides the rotationalpower to the drive sprocket 10.

A plurality of rods 18 are positioned about the radial periphery of thespaced-apart inner rings 12, as shown in FIGS. 1A-C. The rods 18 areconnected to the inner rings 12 such that a portion of each rod 18extends laterally away from each of the inner rings 12 in asubstantially parallel manner relative to the rotational axis of thedrive sprocket 10. In an embodiment, a pair of rods 18 are positionedimmediately adjacent to each other to form a cluster, and each clusteris spaced apart about the periphery of the inner rings 12. In anotherembodiment, each rod 18 is spaced apart from each adjacent rod about theperiphery of the inner rings 12. In an embodiment, the rods 18 arecylindrical, having a circular cross-sectional shape. It should beunderstood by one of ordinary skill in the art that the cross-sectionalshape of the rods 18 can be any shape such as circular, square,triangular, or the like. The rods 18 are configured to engage the guidelugs positioned on the inner surface of a track. In an embodiment, as isshown in FIG. 1A, a portion of the circumferential surface of the rods18 extend radially outward away from the outer peripheral surface 12 aof the inner rings 12 relative to the rotational axis of the drivesprocket 10. As such, the rods 18 extend beyond the inner rings 12 toensure engagement with the base of each guide lug of the track. The rods18 are oriented substantially perpendicular to the flat inner rings 12to which they are attached.

A pair of guide rings 20 are attached to the rods 18, wherein each guidering 20 is attached to adjacent ends of the rods 18 in a spaced-apartmanner, as shown in FIGS. 1A-C. The guide rings 20 are single-pieceannular members oriented in a substantially parallel manner on opposingsides of the spacer 14 and adapter 16. The outwardly-directed surface ofthe guide rings 20 are positioned outwardly from the rods 18. Similar tothe inner rings 12, the rods 18 extend radially outward relative to theouter peripheral surface 20 a of the guide rings 20.

In an embodiment, the outwardly directed surfaces of the guide rings 20are coated with a reduced-friction material such as Teflon®, silicon, orthe like. The reduced-friction material can be a spray-on type, adhesivetype, or other manner of coating the guide rings 20. Thereduced-friction material prevents rubbing and wear against adjacentlugs on the track when operated during dry conditions. However, if thevehicle is being used in a wet environment or on grass which may act asa lubricant, the reduced-friction material is optional. In anotherembodiment, a slide ring 22 which has low friction, wherein the outerperipheral edge of the slide ring 22 is rounded to reduce the impactagainst the adjacent lugs of the track. The slide ring 22 is formed ofnylon 6/6 or other reduced-friction material. The slide ring 22 isformed as a continuous, single-piece annular member having substantiallythe same size and shape as the guide ring 20 to which it is attached.The slide ring 22 is attached to the guide ring 20 by way of a pluralityof screws, but any other fastening mechanism can be used to attach eachslide ring 22 to an outwardly-directed surface of a corresponding guidering 20.

The inner rings 12 and the guide rings 20 can be formed of aluminum,steel, or any other material sufficient to withstand the stressesexperienced during driving a tracked vehicle, particularly the lateralstresses experienced during a turn.

In the embodiment illustrated in FIGS. 2A-C, the drive sprocket 10includes a pair of substantially circular inner rings 12. A spacer 14 ispositioned between the pair of inner rings 12 to allow the inner rings12 to be spaced apart. The thickness of the spacer 14 is between about0.10 inches and about 3.0 inches. The spaced-apart inner rings 12provide lateral stiffness to the drive sprocket 10, particularly withrespect to the lateral forces experienced during a turn of the vehicle.The spacer 14 is sandwiched between the inner rings 12. An adapter 16 ispositioned adjacent to the outwardmost inner ring 12 relative to thevehicle when the drive sprocket 10 is operatively connected to thevehicle. The adapter 16 is configured to engage a drive shaft or otherrotatable shaft that operatively transfers rotation from the engine tothe drive sprocket 10. When the drive sprocket 10 is installed onto thedrive shaft, the adapter 16 is directed away from the vehicle.

In an embodiment, the inner rings 12 and the spacer 14 can be formed asa single member having an equivalent thickness. The spacer 14 allows theinner rings 12 to provide the structural integrity to the rods 18 whilereducing the weight of the drive sprocket 10. In a similar manner, theadapter 16 can also be formed as having a diameter that is substantiallythe same as the inner rings 12. The spacer 14 and adapter 16 areattached to the inner rings 12 to allow the drive sprocket 10 to beattached to the drive shaft from an engine while transferring therotational force to the inner rings 12. In another embodiment, the innerrings 12, spacer 14, and adapter 16 all include a common aperture shapedto receive the drive shaft (not shown) that provides the rotationalpower to the drive sprocket 10.

A plurality of rods 18 are positioned about the radial periphery of thespaced-apart inner rings 12, as shown in FIGS. 2A-C. The rods 18 areconnected to the inner rings 12 such that a portion of each rod 18extends laterally away from each of the inner rings 12 in asubstantially parallel manner relative to the rotational axis of thedrive sprocket 10. In an embodiment, each rod 18 is spaced apart fromeach adjacent rod about the periphery of the inner rings 12. In anembodiment, the rods 18 are cylindrical, having a circularcross-sectional shape. It should be understood by one of ordinary skillin the art that the cross-sectional shape of the rods 18 can be anyshape such as circular, square, triangular, or the like. The rods 18 areconfigured to engage the guide lugs positioned on the inner surface of atrack. In an embodiment, a portion of the circumferential surface of therods 18 extend radially outward away from the outer peripheral surface12 a of the inner rings 12 relative to the rotational axis of the drivesprocket 10. As such, the rods 18 extend beyond the inner rings 12 toensure engagement with the base of each guide lug of the track. The rods18 are oriented substantially perpendicular to the flat inner rings 12to which they are attached.

A pair of guide rings 20 are attached to the rods 18, wherein each guidering 20 is attached to adjacent ends of the rods 18 in a spaced-apartmanner, as shown in FIGS. 2A-C. The guide rings 20 are single-pieceannular members oriented in a substantially parallel manner on opposingsides of the spacer 14 and adapter 16. The outwardly-directed surface ofthe guide rings 20 are positioned outwardly from the rods 18. Similar tothe inner rings 12, the rods 18 extend radially outward relative to theouter peripheral surface 20 a of the guide rings 20.

In some embodiments, the outwardly directed surfaces of the guide rings20 are not coated with a reduced-friction material, nor are guide rings20 equipped with slide ring 22. Therefore, the reduced friction materialand slide ring 22 are optional for guide rings 20.

The inner rings 12 and the guide rings 20 can be formed of aluminum,steel, or any other material sufficient to withstand the stressesexperienced during driving a tracked vehicle, particularly the lateralstresses experienced during a turn.

FIGS. 3A-B show an embodiment of drive sprocket 10 on a tracked vehicle.As was stated above, each track 30 of tracked vehicle has a plurality ofdrive lugs 32 arranged in an annular pattern on the inside surface 31 oftrack 30. Accordingly, in operation, rods 18 of drive sprocket 10 engagea drive lug 32 where drive lug 32 meets inside surface 31 of track 30,thereby rods 18 engage the traction drive lugs 32 of tracks 30 close tothe traction drive lug pitch line, so as to reduce bending moments andstress on the drive lugs 32.

Further, the proposal provides for embodiments of a drive sprocketconstructed of metallic or composite material with u-shaped rings toconnect with rods equally spaced in an annual arrangement. The rods arespaced to engage the track drive lugs near their tooth roots to matchthe track pitch length in a neutral or a slightly under pitch condition.

The following features are incorporated:

-   -   Address off-center mounting of said drive sprocket to the drive        hub    -   Rings with radius corners (U-shape) to improve reaction to guide        & drive lugs        -   U-shape with radius corners guides lugs into self-alignment        -   U-shape adds additional vertical guide rings        -   U-shape with “flat” areas between the guide rings provide            additional support to the track and structural strength to            the drive sprocket

In the embodiment illustrated in FIGS. 4-5, the drive sprocket 10includes an interior ring 40, exterior ring 50, and an intermediate ring60 located between said interior ring 40 and exterior ring 50. Saidinterior ring 40, exterior ring 50, and intermediate ring 60 are spacedapart and centered about the rotational axis of the drive sprocket 10.Interior ring 40 is the inner most ring relative to the tracked vehiclewhen drive sprocket 10 is installed onto the drive shaft of the trackedvehicle. Exterior ring 50 is the outer most ring relative to the trackedvehicle when drive sprocket 10 is installed onto the drive shaft of thetracked vehicle.

Interior ring 40 has an inner guide ring 41, an outer guide ring 43, anda base ring 47. Inner guide ring 41 and outer guide ring 43 arevertically oriented rings relative to the rotational axis of the drivesprocket 10. Further, inner guide ring 41 and outer guide ring 43 aresubstantially parallel.

Inner guide ring 41 is the inner most ring of interior ring 40 and outerguide ring 43 is the outer most ring of interior ring 40 relative to thetracked vehicle when drive sprocket 10 is installed onto the drive shaft(not shown) of the tracked vehicle. Base ring 47 is located betweeninterior ring 40 and outer guide ring 43.

Base ring 47 is a ring having a horizontally oriented width relative tothe rotational axis of the drive sprocket 10. Base ring 47 extends in asubstantially parallel manner relative to the rotational axis ofsprocket 10, thereby bridging between inner guide ring 41 and outerguide ring 43. Further, inner guide ring 41 and outer guide ring 43 aresubstantially perpendicular to base ring 47. A base portion 41 c ofinner guide ring 41 is connected to first side 47 a of base ring 47. Abase portion 43 c of outer guide ring 43 is connected to second side 47b of base ring 47. The transitions between inner guide ring 41 and basering 47, and outer guide ring 43 and base ring 47 are radius corners.

An adapter 16 is fixed to the inside face 43 e of outer guide ring 43and directed toward the tracked vehicle. Adapter 16 and outer guide ring43 share a common center hole 44 and lug holes 45. Adapter 16 and outerguide ring 43 are centered about the rotational axis of the drivesprocket 10. Adapter 16 and outer guide ring 43 are configured to engagea drive shaft or other rotatable shaft that operatively transfersrotation from the engine to the drive sprocket 10.

In some embodiments, outer guide ring 43 has a plurality of lighteningapertures 46, which reduce the weight of outer guide ring 43, whileproviding structural integrity for drive sprocket 10. In someembodiments, adapter 16 can be formed as having a diameter substantiallythe same as outer guide ring 43. In some embodiments, adapter 16 haslightening apertures 46.

As can be seen, inner guide ring 41, outer guide ring 43, and base ring47 of interior ring 40 form substantially a “J” shape, or a “U” shapewith an elongated leg on one side of the “U”. Stated alternatively,inner guide ring 41, outer guide ring 43, and base ring 47 form thecross-section of interior ring 40, which in some embodiments issubstantially a “J” shape or a “U” shape with an elongated leg on oneside of the “U”.

Further, outer guide ring 43 has a first portion 43 a and a secondportion 43 b. The first portion 43 a extends from base portion 43 ctoward the center of outer guide ring 43 for a vertical distance “A”,which is substantially equal to the distance between the base portion 41c and interior edge 42 of inner guide ring 41. Stated alternatively, theheight of the first portion 43 a of outer guide ring 43 is substantiallyequal to the height of inner guide ring 41. Second portion 43 b extendsfrom center hole 44 to first portion 43 a. Accordingly, as can be seen,in some embodiments, first portion 43 a of outer guide ring 43, basering 47, and inner guide ring 41 of interior ring 40 form substantiallya “U” shape. Stated alternatively, in some embodiments, first portion 43a of outer guide ring 43, base ring 47, and inner guide ring 41 formsubstantially a “U” shape cross-section of interior ring 40.

In some embodiments, outer guide ring 43 and inner guide ring 41 ofinterior ring 40 are substantially the same height, thereby outer guidering 43, inner guide ring 41, and base ring 47 form substantially a “U”shape. Stated alternatively, in some embodiments, outer guide ring 43and inner guide ring 41 of interior ring 40 are substantially the sameheight, thereby, in such embodiments, outer guide ring 43, inner guidering 41, and base ring 47 form substantially a “U” shape cross-sectionof interior ring 40.

A spoke assembly 70 is fixed to the outside face 43 d of outer guidering 43 and directed away from the tracked vehicle when drive sprocketis installed onto the drive shaft. Spoke assembly 70 has a spokeassembly ring 71 fixed to outer guide ring 43. Spoke assembly 70 andspoke assembly ring 71 are centered about the rotational axis of thedrive sprocket 10.

Spoke assembly ring 71 has a plurality of spokes 72 projecting towardthe radial periphery of drive sprocket 10. Spokes 72 form an acute anglewith respect to outer guide ring 43. Each spoke 72 has a ring end 73located adjacent to spoke assembly ring 71 and a distal end 75 locatedopposite ring end 73. Distal end 75 of spoke 72 has a tab 76. Slot 74 islocated along spoke 72 between distal end 75 and ring end 73.

Turning now to exterior ring 50, exterior ring 50 has an inner guidering 51, an outer guide ring 55, and a base ring 57. Inner guide ring 51and outer guide ring 55 are vertically oriented rings relative to therotational axis of the drive sprocket 10. Further, inner guide ring 51and outer guide ring 55 are substantially parallel.

Inner guide ring 51 is the inner most ring of exterior ring 50 and outerguide ring 55 is the outer most ring of exterior ring 50 relative to thetracked vehicle when drive sprocket 10 is installed onto the drive shaftof the tracked vehicle. Base ring 57 is located between inner guide ring51 and outer guide ring 55.

Base ring 57 is a ring having a horizontally oriented width relative tothe rotational axis of the drive sprocket 10. Base ring 57 extends in asubstantially parallel manner relative to the rotational axis ofsprocket 10, thereby bridging between inner guide ring 51 and outerguide ring 55. Further, inner guide ring 51 and outer guide ring 55 areoriented perpendicular to base ring 57. A base portion 51 c of innerguide ring 51 is connected to first side 57 a base ring 57. A baseportion 55 c of outer guide ring 55 is connected to second side 57 b ofbase ring 57. The transitions between inner guide ring 51 and base ring57, and outer guide ring 55 and base ring 57 are radius corners.

Inner guide ring 51 has an interior edge 52. Inner guide ring 51 hasrecesses 53 positioned radially about interior edge 52. The radialpositions of recesses 53 correspond to the radial positions of thedistal end 75 of spokes 72 with tab 76, such that each tab 76 is fittedinto a corresponding recess 53. Accordingly, as can be seen, distal end75 of spokes 72 is attached to inner guide ring 51 at interior edge 52.

As can be seen, inner guide ring 51, outer guide ring 55, and base ring57 of exterior ring 50 form substantially a “J” shape, or a “U” shapewith an elongated leg on one side of the “U”. Stated alternatively,inner guide ring 51, outer guide ring 55, and base ring 57 form thecross-section of exterior ring 50, which in some embodiments issubstantially a “J” shape, or a “U” shape with an elongated leg on oneside of the “U”.

Further, inner guide ring 51 has a first portion 51 a and a secondportion 51 b. The first portion 51 a extends from base portion 51 ctoward the center of inner guide ring 51 for a vertical distance “B”,which is substantially equal to the distance between the base portion 55c and interior edge 56 of outer guide ring 55. Stated alternatively, theheight of the first portion 51 a of inner guide ring 51 is substantiallyequal to the height of outer guide ring 55. Second portion 51 b extendsfrom interior edge 52 to first portion 43 a. Accordingly, as can beseen, in some embodiments, first portion 51 a of inner guide ring 51,base ring 57, and outer guide ring 55 of exterior ring 50 formsubstantially a “U” shape. Stated alternatively, first portion 51 a ofinner guide ring 51, base ring 57, and outer guide ring 55 formsubstantially a “U” shape cross section of exterior ring 50.

In some embodiments, outer guide ring 55 and inner guide ring 51 ofexterior ring 50 are substantially the same height, thereby outer guidering 55, inner guide ring 51, and base ring 57 form substantially a “U”shape. Stated alternatively, in some embodiments, outer guide ring 55and inner guide ring 51 of exterior ring 50 are substantially the sameheight, thereby, in such embodiments, outer guide ring 55, inner guidering 51, and base ring 57 form substantially a “U” shape cross-sectionof exterior ring 50.

Turning now to intermediate ring 60, intermediate ring 60 has an innerguide ring 61, an outer guide ring 63, and a base ring 66. Inner guidering 61 and outer guide ring 63 are vertically oriented rings relativeto the rotational axis of the drive sprocket 10. Further, inner guidering 61 and outer guide ring 63 are substantially parallel.

Inner guide ring 61 is the inner most ring of intermediate ring 60 andouter guide ring 63 is the outer most ring of intermediate ring 60relative to the tracked vehicle when drive sprocket 10 is installed ontothe drive shaft of the tracked vehicle. Base ring 66 is located betweeninner guide ring 61 and outer guide ring 63.

Base ring 66 is a ring having a horizontally oriented width relative tothe rotational axis of the drive sprocket 10. Base ring 66 extends in asubstantially parallel manner relative to the rotational axis ofsprocket 10, thereby bridging between inner guide ring 61 and outerguide ring 63. Further, inner guide ring 61 and outer guide ring 63 areoriented perpendicular to base ring 66. A base portion 61 c of innerguide ring 61 is connected to first side 66 a of base ring 66. A baseportion 63 c of outer guide ring 63 is connected to second side 66 b ofbase ring 66. The transitions between inner guide ring 61 and base ring66, and outer guide ring 63 and base ring 66 are radius corners.

Outer guide ring 63 has an interior edge 64. Outer guide ring 63 hastabs 65 positioned radially about interior edge 64. The radial positionsof tabs 65 correspond to the radial positions of slots 74 of spokes 72,such that each tab 65 is fitted into a corresponding slot 74 located atan intermediate position 77 on spoke 72 between ring end 73 and distalend 75. Accordingly, as can be seen, intermediate positions 77 of spokes72 are attached to outer guide ring 63 at interior edge 64.

As can be seen, inner guide ring 61, outer guide ring 63, and base ring66 of intermediate ring 60 form substantially a “J” shape, or a “U”shape with an elongated leg on one side of the “U”. Statedalternatively, inner guide ring 61, outer guide ring 63, and base ring66 form the cross-section of intermediate ring 60, which in someembodiments is substantially a “J” shape, or a “U” shape with anelongated leg on one side of the “U”.

Further, outer guide ring 63 has a first portion 63 a and a secondportion 63 b. The first portion 63 a extends from base portion 63 ctoward the center of outer guide ring 63 for a vertical distance of “C”,which is substantially equal to the distance between base portion 61 cand interior edge 62 of inner guide ring 61. Stated alternatively, theheight of the first portion 63 a of outer guide ring 63 is substantiallyequal to the height of inner guide ring 61. Second portion 63 b extendsfrom interior edge 64 to first portion 63 a. Accordingly, as can beseen, in some embodiments, first portion 63 a of outer guide ring 63,base ring 66, and inner guide ring 61 of intermediate ring 60 formsubstantially a “U” shape. Stated alternatively, first portion 63 a ofouter guide ring 63, base ring 66, and inner guide ring 61 formsubstantially a “U” shape cross-section of intermediate ring 60.

In some embodiments, outer guide ring 63 and inner guide ring 61 ofintermediate ring 60 are substantially the same height, thereby outerguide ring 63, inner guide ring 61, and base ring 66 form substantiallya “U” shape. Stated alternatively, in some embodiments, outer guide ring63 and inner guide ring 61 of intermediate ring 60 are substantially thesame height, thereby, in such embodiments, outer guide ring 63, innerguide ring 61, and base ring 66 form substantially a “U” shapecross-section of intermediate ring 60.

Turning to FIG. 8, a plurality of rods 18 are positioned about theradial periphery of the interior ring 40, exterior ring 50, andintermediate ring 60 of drive sprocket 10. The rods 18 are connected tothe interior ring 40, exterior ring 50 and intermediate ring 60 suchthat a portion of each rod 18 extends laterally away from each of theinterior ring 40, exterior ring 50, and intermediate ring 60 in asubstantially parallel manner relative to the rotational axis of thedrive sprocket 10. In an embodiment, a pair of rods 18 are positionedimmediately adjacent to each other to form a cluster, and each clusteris spaced apart about the periphery of the interior ring 40, exteriorring 50 and intermediate ring 60. In an embodiment, the rods 18 arecylindrical, having a circular cross-sectional shape. It should beunderstood by one of ordinary skill in the art that the cross-sectionalshape of the rods 18 can be any shape such as circular, square,triangular, or the like. The rods 18 are configured to engage the guidelugs 32 positioned on the inner surface 31 of track 30. In anembodiment, rods 18 do not extend beyond inner guide ring 41 of interiorring 40 and outer guide ring 55 of exterior ring 50 relative to therotational axis of drive sprocket 10.

Turning to FIGS. 4, 6, and 8, in an embodiments rods 18 extend beyondthe radial periphery of interior ring 40, exterior ring 50, andintermediate ring 60. Stated alternatively, the rods 18 extend beyondthe outer peripheral surface 48 of the base ring 47 of interior ring 40,outer peripheral surface 58 of the base ring 57 of exterior ring 50, andouter peripheral surface 67 of the base ring 66 of intermediate ring 60.As such, the rods 18 extending beyond outer peripheral surfaces 48, 58,67 ensure engagement with the base of each guide lug 32 of track 30.Further, outer peripheral surfaces 48, 58, 67 of base rings 47, 57, and66 provide flat areas between rods 18 and the inner and outer guiderings 41 and 43 of interior ring 40, the inner and outer guide rings 51and 55 of exterior ring 50, and inner and outer guide rings 61 and 63 ofintermediate ring 60 of drive sprocket 10. The flat areas of outerperipheral surfaces 48, 58, 67 provide additional support to track 30and structural strength to drive sprocket 10.

Drive sprocket 10 can be formed of aluminum, steel, or any othermaterial sufficient to withstand the stresses experienced during drivinga tracked vehicle, particularly the lateral stresses experienced duringa turn.

Turning to FIG. 7, in some embodiments, the distal end 75 of spokes 72is fixed to inner guide ring 51 of exterior ring 50 by welding tab 76 torecess 53. Further, in some embodiments, the remainder of distal end 75abutting of interior edge 52 is also welded to interior edge 52.Additionally, in some embodiments, the intermediate position 77 ofspokes 72 is fixed to outer guide ring 63 of intermediate ring 60 bywelding tab 65 protruding through slot 74 to spoke 72 at intermediateposition 77.

As was stated above, turning to FIG. 8, each track 30 of tracked utilityvehicle has a plurality of drive lugs 32 arranged in an annular patternon the inside surface 31 of track 30. Accordingly, in operation, rods 18of drive sprocket 10 engage a drive lug 32 of tracks 30 close to thetraction drive lug pitch line, so as to reduce bending moments andstress on the drive lugs 32. Further, the “U” and/or “J” shape of theinterior ring 40, exterior ring, 50, and intermediate ring 60 of drivesprocket 10 substantially fill the empty space between drive lugs 32,thereby squaring up rods 18 to drive lugs 32, which further reducesbending moments and stresses on the drive lugs 32 of tracks 30.

Further, as was stated above, the “U” or “J” shape of interior ring 40substantially fills the space between interior guide lug 33 b andinterior drive lug 32 b. Further, the “U” or “J” shape of intermediatering 60 substantially fills the space between exterior drive lug 32 aand interior drive lug 32 b. Additionally, the “U” or “J” shape ofexterior ring 50 substantially fills the space between exterior guidelug 33 a and exterior drive lug 32 a.

Additionally, turning to FIGS. 4 and 8, in some embodiments,discontinuities 80, as seen in FIG. 4, introduced into interior ring 40,exterior ring, 50, and intermediate ring 60 of drive sprocket 10 duringthe metal shaping process are filled in via welding to increase therigidity of interior ring 40, exterior ring, 50, and intermediate ring60, and drive sprocket 10. FIG. 8 shows an embodiment of drive sprocket10 with filled/welded discontinuities 80.

What is claimed is:
 1. A drive sprocket for driving a track of a trackedvehicle, said drive sprocket comprising: an interior ring, an exteriorring, and an intermediate ring situated between said interior ring andsaid exterior ring; said interior ring, said exterior ring, and saidintermediate ring are oriented in a substantially spaced-apart mannerand are parallel with one another, each of said rings having an outerperipheral surface; a plurality of rods attached to said rings adjacentto said outer peripheral surface thereof; and a spoke assembly fixed tosaid outer guide ring of said interior ring; said spoke assembly isconfigured to be directed away from said tracked vehicle when said drivesprocket is mounted on said tracked vehicle; said spoke assembly ringhas a plurality of spokes projecting toward the radial periphery of saiddrive sprocket; said spokes form an acute angle with respect to saidouter guide ring.
 2. The drive sprocket as recited in claim 1, whereinsaid interior ring has a substantially “U” or “J” shape.
 3. The drivesprocket as recited in claim 1, wherein an inner guide ring, an outerguide ring, and a base ring of said interior ring form saidsubstantially “U” or “J” shape of said interior ring, wherein said basering is located between said inner guide ring and said outer guide ring.4. The drive sprocket as recited in claim 1, wherein said base ring,said inner guide ring, and a first portion of said outer guide ring ofinterior ring form said substantially “U” shape of said interior ring.5. The drive sprocket as recited in claim 1, wherein said exterior ringhas a substantially “U” or “J” shape.
 6. The drive sprocket as recitedin claim 1, wherein an inner guide ring, an outer guide ring, and a basering of said exterior ring form said substantially “U” or “J” shape ofsaid exterior ring, wherein said base ring is located between said innerguide ring and said outer guide ring of said exterior ring.
 7. The drivesprocket as recited in claim 1, wherein said base ring, said outer guidering, and a first portion of said inner guide ring of said exterior ringform said substantially “U” shape of said exterior ring.
 8. The drivesprocket as recited in claim 1, wherein said intermediate ring has asubstantially “U” or “J” shape.
 9. The drive sprocket as recited inclaim 1, wherein an inner guide ring, an outer guide ring, and a basering of said intermediate ring form said substantially “U” or “J” shapeof said intermediate ring, wherein said base ring is located betweensaid inner guide ring and said outer guide ring of said intermediatering.
 10. The drive sprocket as recited in claim 1, wherein said basering, said inner guide ring, and a first portion of said outer guidering of said intermediate ring form said substantially “U” shape of saidintermediate ring.
 11. The drive sprocket as recited in claim 1, whereinsaid “U” or “J” shape of said interior ring is configured tosubstantially fill the space between an interior guide lug and aninterior drive lug arranged in an annular pattern on an inside surfaceof a track.
 12. The drive sprocket as recited in claim 1, wherein said“U” or “J” shape of said intermediate ring is configured tosubstantially fill the space between an exterior drive lug and aninterior drive lug arranged in an annular pattern on an inside surfaceof a track.
 13. The drive sprocket as recited in claim 1, wherein said“U” or “J” shape of said exterior ring is configured to substantiallyfill the space between an exterior guide lug and an exterior drive lugarranged in an annular pattern on an inside surface of a track.
 14. Thedrive sprocket as recited in claim 1, said base ring of said interiorring is further comprised of a flat outer peripheral surface locatedbetween said rods and said inner guide ring and said outer guide ring ofsaid interior ring.
 15. The drive sprocket as recited in claim 1, saidbase ring of said exterior ring is further comprised of a flat outerperipheral surface located between said rods and said inner guide ringand said outer guide ring of said exterior ring.
 16. The drive sprocketas recited in claim 1, said base ring of said intermediate ring isfurther comprised of a flat outer peripheral surface located betweensaid rods and said inner guide ring and said outer guide ring of saidintermediate ring.
 17. The drive sprocket as recited in claim 1, whereineach of said plurality of rods is spaced-apart from adjacent rods. 18.The drive sprocket as recited in claim 1, wherein said plurality of rodsform a plurality of clusters, wherein each of said clusters is formed ofa pair of said rods and each of said clusters is spaced apart fromadjacent clusters about said peripheral edge of said inner rings. 19.The drive sprocket as recited in claim 1, wherein said rods arecylindrically shaped having a circumferential surface.
 20. The drivesprocket as recited in claim 1, wherein a portion of saidcircumferential surface of said rods extends radially outward away fromsaid outer peripheral surface of said interior ring relative to arotational axis of said drive sprocket.